A new type of magnetic particle for use in cell selection was developed in the Phase I research. The articles have a compact magnetic core and are coated with a carboxy-functionalized hydrophilic polymer. The particles remain suspended for a few days, but are easily separated magnetically. They are easily redispersed after magnetic separation. The particles have been independently evaluated and shown to offer significant advantages over the currently available magnetic particles. The Phase II research will develop the new particles into a commercial product. The major goal of the research is establishing reproducible procedures for the manufacture of the new magnetic particles. This is the key activity required in order to commercialize the new particles. Scale-up to commercial scale manufacturing and validation of the process will be performed. Two additional important, though less critical, ]ctivities will be developing improving the thermal stability of the hydrophilic coating and provision of alternate functionality on the coating.